Visualizing the causes of airline crashes

There has been a spate of recent high-profile airline crashes (Malaysia Airlines, TransAsia Airways, Germanwings,...) so I was surprised when I saw a time series plot of the number of airline crashes by year, which indicates that the annual number of airline crashes has been decreasing since 1993. The data […]
Post a Comment

Plotting multiple time series in SAS/IML (Wide to Long, Part 2)

I recently wrote about how to overlay multiple curves on a single graph by reshaping wide data (with many variables) into long data (with a grouping variable). The implementation used PROC TRANSPOSE, which is a procedure in Base SAS. When you program in the SAS/IML language, you might encounter data […]
Post a Comment

Plotting multiple series: Transforming data from wide to long

Data. To a statistician, data are the observed values. To a SAS programmer, analyzing data requires knowledge of the values and how the data are arranged in a data set. Sometimes the data are in a "wide form" in which there are many variables. However, to perform a certain analysis […]
Post a Comment

Binary heart in SAS

The xkcd comic often makes me think and laugh. The comic features physics, math, and statistics among its topics. Many years ago, the comic showed a "binary heart": a grid of binary (0/1) numbers with the certain numbers colored red so that they formed a heart. Some years later, I […]
Post a Comment

Twelve posts from 2014 that deserve a second look

I began 2015 by compiling a list of popular articles from my blog in 2014. Although this "People's Choice" list contains many interesting articles, some of my favorites did not make the list. Today I present the "Editor's Choice" list of articles that deserve a second look. I've highlighted one […]
Post a Comment

The distribution of blood types by country

My colleague Robert Allison has a knack for finding fascinating data. Last week he did it again by locating data about how blood types and Rh factors vary among countries. He produced a series of eight world maps, each showing the prevalence of a blood type (A+, A-, B+, B-, […]
Post a Comment

Video: Using heat maps to visualize matrices

One of my presentations at SAS Global Forum 2014 was about the new heat map functions in SAS/IML 13.1. Over the summer I created a short video of my presentation, which gives an overview of visualizing matrices with heat maps, and describes how to choose colors for heat maps: If […]
Post a Comment

How to choose colors for maps and heat maps

Have you ever looked as a statistical graph that uses bright garish colors and thought, "Why in the world did that guy choose those awful colors?" Don't be "that guy"! Your choice of colors for a graph can make a huge difference in how well your visualization is perceived by […]
Post a Comment

Create discrete heat maps in SAS/IML

In a previous article I introduced the HEATMAPCONT subroutine in SAS/IML 13.1, which makes it easy to visualize matrices by using heat maps with continuous color ramps. This article introduces a companion subroutine. The HEATMAPDISC subroutine, which also requires SAS/IML 13.1, is designed to visualize matrices that have a small […]
Post a Comment

Designing a quantile bin plot

While at JSM 2014 in Boston, a statistician asked me whether it was possible to create a "customized bin plot" in SAS. When I asked for more information, she told me that she has a large data set. She wants to visualize the data, but a scatter plot is not […]
Post a Comment